Though infant immune systems raise risk of infection, they also allow good microbes into the body

By Nathan Seppa, 11:35 AM November 6, 2013

The seeming failure of newborns to muster a robust defense against infections is a trade-off that delivers long-term benefits, a new study suggests. In infants, the body’s immune army stands down for a month or two and then gears up. While this gap leaves babies at risk of infection, it also may allow beneficial bacteria to populate an infant’s intestines, a development that carries lifelong advantages, researchers working with mice report November 6 in Nature.